Are Constants Constant?

The prospect of a time-dependent Higgs vacuum expectation value is examined within the standard model of electroweak interactions. It is shown that the classical equation of motion for the Higgs field admits a solution that is a doubly-periodic function of time. The corresponding Dirac equation for the electron field is equivalent to a second order differential equation with doubly-periodic coefficients. In the limit of very large primitive period of the Higgs background this equation can be solved in WKBJ approximation, showing plane-wave solutions with a time-dependent distortion factor which can be made arbitrarily small.